The present invention is directed to a bi-directional refrigerant expansion and metering valve for use in a minisplit air conditioner, a heat pump system, or an air conditioning system. The bi-directional refrigerant expansion and metering valve is an alternative to metering valves, to capillary tube and to other expansion valve concepts.
Present heat pump systems either require two metering valves with differing diameters and differing short tube length to diameter ratios in order to properly operate, or fail to fully utilize bi-directional valves. The use of two metering valves is subsequently discussed with regard to FIGS. 1A and 1B. Most bi-directional metering valves are complex spring loaded or shuttle arrangements such as are shown in U.S. Pat. Nos. 5,029,454 to Eisberg, 5,052,192 to Drucker, and 5,038,579 to Drucker. The spring or shuttle changes position to compensate for changes in flow direction. However, these patents fail to recognize that controlling the geometry of both ends can control the flow rate entering those respective ends. The bi-directional valve of U.S. Pat. No. 5,345,780 recognizes the advantages of controlling the approach to one end of a short tube restrictor but fails to appreciate the advantages of controlling both approaches.
It would be advantageous to minimize the number and type of refrigerant expansion and metering components.